5.1  Anatomy and function of the eye

You first need to study the structures of the human eye and their functions. Knowing this will help you understand about the different causes of blindness, such as cataract. As you read the following descriptions, see if you can identify the structures in Figure 5.1, which intentionally has no labels.

Figure 5.1  The human eye, front view. (Adapted from: The Open University, 2008, Visual Impairment: A Global View, SDK125, Case Study 7, p.13)

The eyeball is a small organ in size, only about 2.5 cm in diameter, but it serves a very important function, which is your sight. Vision is the primary means that you use to gather information from your surroundings. The eye is usually compared to a camera. Each eye gathers light and transforms it into signals to your brain, which interprets what you see as a picture or image. Both the eye and the camera have lenses to focus the incoming light so that the image formed will be clear and understandable.